Camera Memory Speed
Memory Card Comparison & Performance Tests for Digital Cameras
Pentax K-3 II Dual SD card slots with door open

Pentax K-3 II SD Card Comparison

The Pentax K-3 II is an advanced APS-C DSLR with a 24MP sensor aimed at enthusiast and professional photographers. The built-in anti-shake system enables a new high resolution "Pixel Shift" mode to combine four images into one for increased detail and color depth. The K-3 II is capable of up to 8.3 fps continuous shooting and uses a 27-point auto focus system. The magnesium alloy and stainless steel body is weather sealed and cold-proof and has built-in GPS. The camera has dual card slots supporting SD, SDHC and SDXC memory cards including UHS-I.

To compare memory card performance, 56 SD cards were tested in the K-3 II. The tests uncovered some interesting characteristics of the K-3 II, including its buffer capacity and behavior with the buffer full. The results are presented in write speed for RAW images. The second table compares the number of images taken in 30 seconds of continuous shooting for RAW+JPEG, RAW and JPEG image modes. Further details and observations from the tests provided in the analysis. A selection of Recommended SD cards for the K-3 II reveals the fastest cards as well as the best value for this camera.

Camera Details and Settings

The target scene used in these tests simulates what might be typical of sports or wildlife photography. The static subject under controlled lighting has some areas with detail in focus and some background elements out of focus (the same scene used in the Canon T6s/T6i test). The K-3 II is mounted on a tripod and operated by a remote timer to provide 30 second shooting intervals. Focus is verified using Live View at maximum magnification.

The average continuous write speed is calculated by dividing the amount of data written divided by the write time. The results are in MB/s (1 MB = 1,048,576 bytes). Write time is determined using the card access light. The access light in the K-3 II yielded consistent measurements and through multiple tests using various shooting durations.

A manual lens is used for consistency throughout the tests. Maximum frame rate with a manual lens in M mode was about 5.5 fps. Setting the camera to Av mode (even though the camera did not control the aperture) with exposure compensation to change shutter speed provided just over 8 fps. At shutter speeds below 1/200 the frame rate was reduced more than would be expected from the additional shutter duration (1/125 provided just over 7 fps, 1/100 provided around 6.4 fps).

Pentax K-3 II SD Card Write Speed

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Memory CardSize
Average Write Speed (MB/s)Price
SanDisk Extreme Pro 95MB/s 64GB6437.2$34.95
SanDisk Extreme 80MB/s 256GB25637.2$141.58
SanDisk Extreme Pro 95MB/s microSDXC 64GB6437.1$52.99
SanDisk Extreme 80MB/s 128GB12837.0$68.97
SanDisk Extreme Pro 95MB/s microSDHC 32GB3236.7$32.95
SanDisk Extreme Plus 80MB/s 64GB6436.7$64.95
Gobe Magic 104MB/s 64GB6436.6$145.99
SanDisk Extreme 60MB/s 64GB6436.6$53.99
Lexar Professional 2000x UHS-II 32GB3236.6$54.95
SanDisk Extreme U3 microSD 64GB6436.4$38.99
Samsung PRO 64GB6436.4$52.73
Lexar Professional 633x U3 64GB6436.4$38.95
SanDisk Extreme Plus 80MB/s microSD 32GB3236.3$24.95
SanDisk Extreme Pro 95MB/s 32GB3236.2$21.95
SanDisk Extreme 60MB/s 32GB3236.2$29.99
Kingston U3 90/80 MB/s 64GB6436.2$32.40
SanDisk Extreme U3 microSD 32GB3236.1$19.99
Transcend R95 W85 U3 64GB6436.0$48.89
Transcend 95/60 MB/s U3 64GB6435.9$27.84
Samsung PRO 32GB3235.9$29.99
SanDisk Extreme Plus 80MB/s 32GB3235.8$34.95
Kingston U3 90/80 MB/s 32GB3235.5$17.99
Lexar Professional 600x 64GB6435.2$47.93
Toshiba Exceria Pro UHS-II 32GB3235.2$113.18
Lexar Professional 1000x UHS-II 128GB12835.1$59.00
Toshiba Exceria UHS-I Class 3 64GB6435.1$29.95
SanDisk Extreme 45MB/s 32GB3234.8$16.95
Toshiba Exceria Type 1 32GB3234.7$137.68
Sony 95MB/s U3 64GB6434.6$41.95
Transcend 95/85 MB/s U3 32GB3234.6$22.99
Gobe Magic 104MB/s 32GB3234.6$59.95
Lexar Professional 1000x UHS-II 32GB3234.5$22.46
Sony 94MB/s 32GB3234.4$26.29
PNY Elite Performance 64GB6434.1$34.95
Kingston Class 10 UHS-I 64GB6434.0$28.95
Patriot EP Pro 90MB/s 32GB3233.7$24.64
Transcend 600x 64GB6433.7$28.99
Toshiba Exceria UHS-I Class 3 32GB3233.6$24.95
Sony 95MB/s U3 32GB3233.6$24.99
Kingston Ultimate 32GB3233.5$14.32
Panasonic Gold Series 32GB3233.3$34.95
SanDisk Extreme Pro 280MB/s UHS-II 32GB3232.7$57.08
Lexar Professional 633x U3 32GB3232.5$29.99
Lexar Professional 600x 32GB3231.7$55.37
Patriot EP Pro 90MB/s 64GB6429.9$27.99
Lexar Professional 400x 32GB3229.7$13.95
Toshiba Exceria Type 2 32GB3228.8$68.07
PNY Elite Performance 90MB/s 32GB3227.3$19.95
Transcend 600x 32GB3226.9$12.99
Panasonic MicroP2 UHS-II 32GB3226.7$189.99
SanDisk Ultra 40MB/s 32GB Card 23217.6$13.69
Samsung EVO 32GB3216.2$9.99
SanDisk Ultra microSD 64GB6416.1$24.95
SanDisk Ultra 40MB/s 64GB6414.5$24.29
SanDisk Ultra microSD 32GB3212.8$13.95
Toshiba FlashAir II 32GB3211.9$49.95

Pentax K-3 II Continuous Shooting

The continuous shooting test is a measurement of the number of shots the K-3 II can take when shooting continuously for 30 seconds. This differs from the write speed test which measures the write time (that continues past 30 seconds). Image modes used for the continuous test are RAW+JPEG, RAW, and JPEG. The RAW format used was DNG. (PEF format produced similar file sizes and results.) The JPEG setting is large, highest quality (***). The camera is set to continuous high release mode, and at 1/200 shutter it shot at just over 8fps before dropping to lower frame rates, depending on the memory card. The average RAW (DNG) file size was 28.2 MB and the average JPEG file size was 9.6 MB.

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Memory CardSize
Continuous Shooting – Images in 30 SecondsLowest
SanDisk Extreme Pro 95MB/s microSDXC 64GB645871127$52.99
SanDisk Extreme 80MB/s 128GB1285871126$68.97
SanDisk Extreme Pro 95MB/s 64GB645871126$34.95
SanDisk Extreme 80MB/s 256GB2565871125$141.58
SanDisk Extreme Pro 95MB/s microSDHC 32GB325770128$32.95
Lexar Professional 2000x UHS-II 32GB325770128$54.95
SanDisk Extreme 60MB/s 64GB645770126$53.99
Samsung PRO 64GB645770126$52.73
SanDisk Extreme Plus 80MB/s 64GB645770126$64.95
SanDisk Extreme U3 microSD 64GB645770125$38.99
Kingston U3 90/80 MB/s 64GB645770125$32.40
SanDisk Extreme Pro 95MB/s 32GB325769128$21.95
SanDisk Extreme 60MB/s 32GB325769127$29.99
SanDisk Extreme U3 microSD 32GB325769127$19.99
SanDisk Extreme Plus 80MB/s microSD 32GB325769127$24.95
Samsung PRO 32GB325769127$29.99
Transcend R95 W85 U3 64GB645769120$48.89
Gobe Magic 104MB/s 64GB645670125$145.99
SanDisk Extreme Plus 80MB/s 32GB325669125$34.95
Kingston U3 90/80 MB/s 32GB325669125$17.99
Gobe Magic 104MB/s 32GB325668125$59.95
Toshiba Exceria Pro UHS-II 32GB325668124$113.18
SanDisk Extreme 45MB/s 32GB325668124$16.95
Toshiba Exceria Type 1 32GB325668124$137.68
Transcend 95/85 MB/s U3 32GB325668124$22.99
PNY Elite Performance 64GB645666125$34.95
Transcend 95/60 MB/s U3 64GB645569125$27.84
Toshiba Exceria UHS-I Class 3 64GB645569123$29.95
Kingston Class 10 UHS-I 64GB645568124$28.95
Sony 94MB/s 32GB325568123$26.29
Sony 95MB/s U3 64GB645568123$41.95
Transcend 600x 64GB645565120$28.99
Lexar Professional 1000x UHS-II 128GB1285468124$59.00
Lexar Professional 1000x UHS-II 32GB325468119$22.46
Patriot EP Pro 90MB/s 32GB325467122$24.64
Kingston Ultimate 32GB325467122$14.32
Panasonic Gold Series 32GB325467121$34.95
Sony 95MB/s U3 32GB325467120$24.99
Lexar Professional 633x U3 32GB325466122$29.99
SanDisk Extreme Pro 280MB/s UHS-II 32GB325466119$57.08
Lexar Professional 600x 32GB325465122$55.37
Lexar Professional 600x 64GB645370125$47.93
Lexar Professional 400x 32GB325364117$13.95
Toshiba Exceria UHS-I Class 3 32GB325267122$24.95
Lexar Professional 633x U3 64GB645170125$38.95
Toshiba Exceria Type 2 32GB325063112$68.07
PNY Elite Performance 90MB/s 32GB325062116$19.95
Transcend 600x 32GB325062116$12.99
Panasonic MicroP2 UHS-II 32GB325061111$189.99
Patriot EP Pro 90MB/s 64GB644864117$27.99
SanDisk Ultra 40MB/s 32GB Card 2324353101$13.69
Samsung EVO 32GB32425197$9.99
SanDisk Ultra microSD 64GB64424996$24.95
SanDisk Ultra 40MB/s 64GB64414997$24.29
SanDisk Ultra microSD 32GB32404892$13.95
Toshiba FlashAir II 32GB32404792$49.95


The Pentax K-3 II has a large buffer. It can capture between 23-25 RAW (and RAW+JPEG) images at full frame rate just above 8fps regardless of the memory card used. The difference between 23 and 25 shots depended on the image subject and shutter speed. Using a faster card did not seem to affect the number of images buffered at the full frame rate, but it did affect what happened after the frame rate dropped from 8fps. When then the frame rate drops, it first uses an intermediate frame rate. At this point the camera is still taking shots faster than the write speed, at about 2 fps. The card speed determined the length of this intermediate condition, faster cards took more shots (up to 36 using the medium detail test scene) at the intermediate rate, while slower cards dropped to a lower rate sooner (after only 9 shots). The lowest frame rate is determined by the card speed, because at this point the camera only allowed shots to be taken at the same rate of its ability to clear the buffer. This rate varied between 1.3 fps for the faster cards and 0.4 fps for the slower cards. The amount of data cleared after a long period continuous shooting of RAW images averaged about 900MB.

The Pentax K-3 II write speed is an average speed over a long period of continuous shooting. The camera frame rate changes throughout shooting as the buffer fills, but its write speed is consistent. The write speed depends on several factors, the most important being the memory card, but file size also affects the results. Large files have a higher average speed than small files because writing more separate files requires more overheard. The write speed results above use an average detail subject (28.2 MB file size). When testing with a very detailed subject (38.5 MB file size) average write speeds were up to 4% faster. Even with the large file size, the average speed was just below 40MB/s. The Pentax K-3 II supports UHS-I cards. Using UHS-II cards in the K-3 II does not improve performance because they revert to UHS-I mode when used in the camera.

Comparing memory card performance in the K-3 II shows there is not much difference when using the fastest cards. The K-3 II has a large buffer which helps compensate for slower cards. The camera's limited write speed equalized the fast cards. When shooting up to 23-25 shots (RAW or RAW+JPEG) the card speed did not affect performance. The card speed did affect amount of shots at intermediate frame rate (~2fps) after the first 23-25 shots in RAW modes, as well as determining the very lowest frame rate, which is reached only after several seconds of continuous shooting.

In JPEG mode the K-3 II was even less dependent on memory card speed, capturing between 68 and 71 shots at full frame rate, using the medium detail test scene. After the initial burst, the frame rate dropped to a low rate according to the card write speed (unlike RAW and RAW+JPEG, JPEG mode did not have an intermediate frame rate).

SD card write speed is not perfectly consistent. Cards exhibit occasional delays that affect average speed, especially over a long test duration. This was most apparent in RAW+JPEG results. Several cards were tested multiple times, those that were less consistent tend to show slightly lower than expected RAW+JPEG performance (compared to RAW or JPEG performance alone) which continued even after multiple retests.

Recommended SD Cards for the Pentax K-3 II

Fastest UHS-I card
SanDisk Extreme Pro 95MB/s UHS-I SD Card
SanDisk Extreme Pro 95MB/s UHS-I SD Card

The fastest SD card measured in the Pentax K-3 II was the SanDisk Extreme Pro 95MB/s UHS-I 64GB SDXC Card. The same card in microSDXC format also provided similar performance. The new SanDisk Extreme 80MB/s cards in 128GB and 256GB capacities also provide high write speeds. The margin between the top SD cards is so small that there would be little difference experienced in this camera, even after 30 seconds of continuous shooting. The Extreme Pro 280MB/s UHS-II card did not perform as well as the UHS-I Extreme Pro cards in the K-3 II.

Beyond the SanDisk cards, the Gobe Magic 64GB, Lexar Professional 2000x UHS-II 32GB, Samsung PRO 64GB, and Lexar Professional 633x 64GB cards provide excellent write speed in Pentax K3 II. Pentax K-3 II camera with USB cable in side port and open door

Downloading images from the Pentax K-3 II

The K-3 II has a built-in USB 3.0 port that can be used to transfer images from the camera to a computer or other host device. USB 3.0 can provide high transfer speed, but the K-3 II is a limiting factor. The camera has two transfer modes, MSC and PTP. In MSC mode the transfer rate averaged 36.0MB/s, while in PTP mode the average speed was 19.0MB/s. The transfer speed was measured while transferring 127 RAW images (about 3.5GB total) from a SanDisk Extreme Pro 95MB/s 64GB SDXC card in the camera to a computer with a USB 3.0 cable, USB 3.0 port and SSD drive. The transfer speed measured not much above USB 2.0 performance. When using a separate USB 3.0 card reader, the same card provides about 90MB/s download speed when transferring the same images. Further card reader tests and benchmarks can be found in the Card Reader Reviews.